Stent Distortion Seen With Certain Products

Some researchers have expressed concern that longitudinal stent compression may occur more frequently with specific types of stents -- namely the European-approved Element and Omega, and the FDA-approved Ion.

In a case report, "accordioning" and shortening of an Ion stent appeared to be related to a subsequent myocardial infarction after it became occluded, Cindy Grines, MD, of Wayne State University in Detroit, and colleagues reported in the Journal of Interventional Cardiology.

Also, in a past report, employees of a competing stent manufacturer found that the Element family may shorten up to 46% under the force that an interventional cardiologist could potentially exert to advance a balloon or ultrasound device into the artery.

The findings "should raise concerns regarding the use of the Element, Omega, or Ion stent platforms, particularly in tortuous vessels where the stent may be snagged by the balloon or other adjunctive devices," Grines and colleagues wrote.

The issue of stent compression garnered much attention at last week's Transcatheter Cardiovascular Therapeutics meeting, where researchers discussed several other cases and bench-testing studies. Consensus held that it was a rare occurrence and usually confined to the most complex cases, but also that further study was needed.

In the present case report, a 65-year-old male who needed stenting in his right coronary artery was given a Taxus Ion drug-eluting stent, manufactured by Boston Scientific. Grines and colleagues said it was difficult to advance the stent through the lesion because of tortuosity and calcification, and it took two attempts to place the stent in the target location.

However, they said there was some snagging of guide wires on the proximal edge of the stent, and an angiogram showed that both the proximal and distal portions "appeared to be deformed, accordioned, and shortened."

Five days after the procedure, the patient came back to the emergency department with chest pain, and was found to be having a myocardial infarction.

His clinicians saw that the right coronary artery was completely occluded proximally, just in front of the stent. They tried but failed to advance a wire past the proximal end, and concluded that stent thrombosis was likely due to "stent deformation and probably malapposition."

Ultimately, the vessel remained blocked and the MI was treated medically, they wrote.

At TCT, employees of Abbott Vascular presented a study that was simultaneously published in EuroIntervention, which found the Element family of stents (also made by Boston Scientific) may shorten up to 46% under the force that an interventional cardiologist would potentially exert to advance a balloon or ultrasound device into the artery.

Grines and colleagues noted that in the Manufacturer and User Facility Device Experience (MAUDE) database between April 2009 and May 2011, there were 358 complaints about Element, of which 288 had further descriptions for analysis.

Among those, 14.9% reported stent length change, 8% reported crimped stent damage, and 2.1% said malapposition -- all of which "seemed to describe a problem with longitudinal strength of the Taxus Element and Omega stent design," they wrote.

Both of those are approved only overseas, though the Taxus Ion -- the FDA-approved version of the Taxus Element -- was okayed by the FDA last April.

Grines also wrote in an accompanying editorial that this is the first case of longitudinal stent compression of the Ion stent in 25 years in practice.

She called the bench-testing results "very disturbing," even though she expressed caution about the potential conflict of interest.

"Until further data are available, our institution will use the Ion stent cautiously, and only when alternatives are unavailable for the size under consideration," she said.

She added that the FDA and Boston Scientific are aware of the issue and an investigation is ongoing.

Gregg Stone, MD, of Columbia University Medical Center, who led many discussions about stent compression at TCT, said this case and the serious complication tied to it don't change his perception about the issue.

"Longitudinal stent deformation occurs rarely, but can be associated with adverse events," he told MedPage Today in an email. "It is more prone to occur with some stent designs than others, and represents a tradeoff made to achieve greater stent flexibility and deliverability."

He noted, however, that this is "only one attribute of a stent that must be considered when evaluating overall clinical performance," including propensity to fracture, embolize, balloon rupture, and polymer reactions.

Accessibility Statement

At MedPage Today, we are committed to ensuring that individuals with disabilities can access all of the content offered by MedPage Today through our website and other properties. If you are having trouble accessing www.medpagetoday.com, MedPageToday's mobile apps, please email legal@ziffdavis.com for assistance. Please put "ADA Inquiry" in the subject line of your email.